Clothes dryer



Dec. 3, 1957 P. L. FOWLER 2,814,886

CLOTHES DRYER 4 Sheets-Sheet 1 Filed Dec. 27. 1954 @JLJWM Dec. 3, 1957 Filed Dec. 4 Sheets-Sheet 2 55 57 J 79 52- 79 16 4a j0- 0 o 0 c -76 5&1 -65 M @5- 75 75 W/E/v TUE" ,PAUL L. FOWLER Dec. 3, 1957 P. L. FOWLER 2,814,886

' CLOTHES DRYER Filed Dec. 27. 1954 4 Sheets-Sheet 5 //\/ME/\/TUF PAUL. 1.; FOWLER EM Mmq A TTUF/VE W5 P. L. FOWLER Dec. 3, 1957 CLOTHES DRYER Filed Dec. 27. 1954 4 Sheets-Sheet 4 United States Patent ice CLOTHES DRYER "laul L. Fowler, Osw'ego, Oreg. Application December 27, 1954, Serial No. 477,739 9'Claims. (Cl. M -133) Thelpresent invention relates to a clothes dryer, and --more specifically relates to improvements in rotatable "drurrutypedryers utiliii'ng air heating and air circulating 'rheans.

An important object of the invention is to :provide a clothes dryer, primarily intended for home use, 'which is simple and compact in structure, reliable and efficient in operation, and economical 'to manufacture.

Another important object is to :provide a top zloa'ding clothes dryer.

A fur-then object is to provide a dry'er mechanism which "can "be used in either a top loading or "a side loading cabinet.

A-further* object is't'o provide adryer mechanism which "can be housed either in a portable cabinet or in a permanent :part of a house structure.

A further -object is to l provide a drying drum 'having an air .passage 'thereth'rough which =cannot "be "blocked 'by laundry in the drum.

A further object =is 'tosprovid'e a dryer rnechahism 'hav- -ing a drum rotatable on a horizd'ntal axis and equipped with improved bearing and air sealing means.

-A' fnrthr object is to providea dryer mechanism hav- -'ing "a hot air passageway "through hollow s'upporting stanchions orp'e'clest als fora horizohtalrotatable clothes containing drum.

A further'object is "iOEPIOVidC a dryer mechanism emj'ploying a "rotatable drum having an imperforate peripheral wall and perforated end walls for "directihg heated air axially "through said 'd'rum.

A further object is=to provide am'ovebdrive means for a rotatable dryer "drum wherein the peripheral sur'f'a'ce of the drum serves as 'the drive sheave for a V-helt.

A further object is to provide a"drive'belt arrangement for a'rotatable clothes drying drum utilizi-ng'n'ovel tension means to 'maintain said drive belt in frictional en- ;gagement with said drum.

A further object is to provide "a control system for a 'dru'rn type clothes "dryer having improved control and safety features.

-Still-another-objectis to provide adryer of the type described which is relatively quiet and vibrat-ionless in operation.

The present invention-resides in a si-mplified-and com- .pact drying mechanism designed primarily for 'home 'laundry use, and, in general, comprises an outer casing and inner operating structure mounted on a common base but not otherwise connected together. The operating structure comprises a rotatable "clothes receiving d'rum, an air passageway structure'communicating with end openings in the'dru'm, a heatingunit in the "air passag'eway, amotor mechanism for "drivingthedrum, and a 'suctionfan' for circnlating the heated air. "'A p'or- 'tion 6f the air -"passa e'way comprises -a pair of hollow =uprightstanchions or'pedestals, and" the clothes reciying drum is-rotatably filountd on ahorizontal axis en' said -"stan'chibns. The outer casifig has an opening 'initSt'op wall and a lid therefor, and the rotatable drum has a 2,814,886 Patented Dec. 3, 1957 :hinged door :in its peripheral wall adapted to be moved into alignment with said casing opening, thereby permitting loading and unloading of the drum from the top side of the dryer. The motor rotates the clothes receiving drum by means of a V-belt arrangement providing a frictional drive, and also operates a fan for circulating air through the "dryer. A simple electrical control "system is provided for operating the machine for predetermined lengths of time, and safety switch and thermostats are also provided to de-energize the circuits upon the existence of certain conditions.

The invention will be better understood and additi'onal objects and advantages will become apparent from the following description taken in connection with the accompanying drawings which illustrate a preferredform of the device. It is to be understood, however, that the invention may take other forms, and that all such modifications and variations within the scope of the appended claims which will occur to persons skilled in the art are included in the invention.

in the drawings:

*Figure l-"i's aperspective view showing the front of the y Figure 2 is :a perspective view showing the rear of the dryer;

Figure 3 :is a perspective view of the dryer with the lid in open positionand-showing the rotatable drum within the casing;

Figure 4 is 'a'wiri'ng diagram of the controlsystem;

Figure -5 is a-horizontal sectional view showing the rotatable drum structure and mounting means therefor,

taken'on the line 5--5 of Figure 2;

Figure 6xis Iaipers'pective view of the base and drum =supp'o'rting 'stanchions;

Figured is asectionalview taken on the line 7-4 of Figure 6, showing the drive means for the drum and fan which are not' shown in Figure 6;

Fignre 8 is ia sectional view showing the drive belt tensioning means, itakenon the line 88'of Figure 7;

-'Figure 9 is a sectionalwiew showing vibration zdampening m'eans on the motor mount, :taken on'the line 99 of Figure -7;

F-ig ur'e 10'is a verticalsectional view=tal en on the line "10-=-1-0 of Figure 5; t and Figure :1 1 is a sectio'nal'view taken 'on the line :11-11 of Figure 33 andr showing in detail the latch lrneehanism for the drum door.

Referring tome-drawings, and specifically to Figures 1, 2, -:a'nd :8, -the pres'ent dryer comprises "a cabinet or casing =15,prefer ab'ly ofa metallic structu're'with ab'aked enamel exteriorrfinish. casing 15:ha's a-front wall "16 having a lower sloping portion l 7 provi'cled with'a'plurality of louvers 18. The ca'sing has si'de walls 20 and "a 're'a'r wall 221. T Rear wall 21 has a "vertical t opening *or :slot =22, Figures 2 and 7, adjacentonesi'd'e, and this openin'g is covered by an exterior lint receptacle 23 having an open front wall which lies over the opening 22 an'cl havi'ng a screene'd baok Wall324 foreatching lint Which-may he carried in the dr-yerair stream. Lint receptacle 2Z3 'isrprovided with fright angular flange-portions 25, Figure 5,fslidably errgageable with a pairof=braekets 26 secured tb back wall 21 a'nd has a bracket 27 on its top end which serves as a ha'ndle for =-sliding the receptacle vertically out-6f engagement with the brackets 26 when it is-desired to 'c'lean the screen portion ofthe receptacle -"or o'the'rwise remove the lint receptacle. T he lintreceptacle may be -"con'nected "with a suitable fine when it is I not "desired to discharge humid air into the laundry room.

Casing 15 has a top wall 30 with a lid 31 hinged at'32 and' eqnipped with ahandle 33. A base 3'5fFigure 10,

raise the floor of the base a short distance off the floor and which serves also as a means for mounting the casing 15 by means of bolts 37. Secured on the base 35 adjacent one corner thereof is a terminal box 40 for receiving a three wire conductor assembly 41.

Referring now to Figures and 6, two hollow stanchions or pedestals 50 and 51 are secured to the base 35 by means of flange portions 52 and 53, respectively, on the pedestals. Each of the two pedestals 50 and 51 comprises a tubular structure with an interior passageway for the movement of air therethrough. Pedestal 50 is provided with a plurality of openings 56 on its inner facing wall adjacent the upper end thereof. Pedestal 50 is also provided with a circular opening 57 on its inner facing wall adjacent the lower end thereof. Secured to the pedestal 50 is a horizontal duct 60 having a closed end 61 and a discharge end 62. The interior of the duct 60 communicates with the opening 57 in the pedestal 50 so that air currents can freely enter the openings 56 and be discharged through opening 62 in the duct 60.

Pedestal 51 is provided with a plurality of openings 65 on its inner facing wall adjacent the upper end thereof and also has an opening 66 adjacent the lower end thereof for receiving atmospheric air which enters the casing 15 through the louvers 18. Mounted interiorly of the pedestal 51 is a heating unit 67 adapted to heat air moving through the dryer. As seen in Figure 5, the outer wall surface of each of pedestals 50 and 51 is insulated acoustically and thermally from the side walls of the casing 15 by insulation batts 68.

The pedestals 50 and 51 have axially aligned trunnions 69 rigidly secured as by welding to each of the two Walls of the pedestals, a portion of said trunnions projecting from the inner facing wall. Rotatably mounted on the trunnions 69 is a clothes drying drum 70 having end bearings 71 engageable with the projecting portions of trunnions 69. The peripheral wall of drum 70 comprises an imperforate cylindrical sheet but the end Walls 74 of the drum are provided with annular screen portions 75, Figures 5 and 10, which permit air to move axially through the drum.

The end walls 74 of the drum are provided with an annular seal 78, Figure 5, comprising a flexible strip having a curved cross section. One edge of the sealing strip is secured to the end wall of the drum by means of screws 79 and its other edge is held in continuous engagement with the inner facing wall of the adjacent pedestal by a coiled tension spring 80 seated in the groove of the seal. The seals 78 circumscribe the holes 56 and 65 in the respective pedestals as well as the screened portions 75 on the ends of the rotatable drum, and by this structure air is adapted to be circulated between the hollow pedestals through the drum without escaping into the area exteriorly of the drum. Atmospheric pressure assists the spring 80 in holding the free edge of the seal against the inner face of the pedestal since the pressure in the drum is below atmospheric pressure.

Referring to Figures 3 and 10, the drum 70 is provided with a door 82 on its peripheral surface, the door portion being curved to conform to the general peripheral contour of the drum. Door 82 is hinged at 83 parallel to the drum axis, and is held in a closed position by a latch 84. Latch 84 comprises a U-shaped spring catch 84a riveted to a plate 84b secured to the drum door 82. Plate 841) has an aperture 84c to reecive one arm of the spring catch 84a, and the drum wall is provided with an aperture 84d to receive the body portion of the catch 84a, the aperture 840! and catch 84a being of a size such that a firm frictional grip is maintained therebetween when the door is shut. Door 82 is latched shut by downward pressure thereon sufiicient to snap catch 84a into aperture 84d, and the door is released by moving the arm which projects through aperture 84c in a direction to compress the catch body.

The interior surface of the drum 70 is provided with a plurality of ribs 86 which extend parallel to the axis of rotation of the drum and which project radially inwardly. Ribs 86 are preferably formed of sheet metal or the like, and preferably assume a U-shape in cross section, as shown in Figure 10. A pair of end blocks 87 are secured to the ribs 86 and are bolted to the end walls of the drum by bolts 88, Figure 5, for supporting the ribs. The ribs 86 are engageable by the clothes as the drum rotates and prevent the clothes from being bunched or wadded together. The clothes are thereby tumbled by the revolving drum and maintained in a fluifed and loose condition during the entire drying cycle so that air circulating in the drum will be permitted to penetrate all portions of the clothes.

Means for driving the drum and drawing heated air through the drum are shown in Figures 6, 7 and 8. The driving mechanism comprises an electric motor 90 secured to a mounting bracket 91. Bracket 91 comprises a pair of plates 92 secured in horizontal position to the side wall of duct 60. The free ends of the plates 92 are secured to an upstanding plate 93 having an inclined leg portion 94 secured to the base 35. Referring specifically to Fig. 9, the plates 92 are provided with a right angular flange 96 and mounted between the flanges 96 and the plate 93 are rubber bushings 97. Bushings 97 are held in place by bolts 98 and serve to resist the transmission of vibration from the motor to the frame structure.

Motor 90 is mounted on the plate 93 by means of screws 100, as shown in Figure 7, and the motor is held in spaced relation from the plate by means of sleeves 101 on screws 100. Motor 90 has an extended shaft 103 projecting through the plate 93 and also through the side wall of duct 60, the duct 60 having an opening 104 for receiving the shaft, Figure 6. Mounted on the shaft 103 between the plate 93 and the duct 60 is a drive pulley 106 for driving a V-belt 107. Pivotally mounted on plate 93 by a pin 109 closely adjacent the motor shaft is an arm 110 having an ofiset end portion 11. Also pivotally mounted on the pin 109 is a second arm 112 which, together with the arm 110, forms a yoke for supporting a shaft 113 adjacent the outer ends thereof. Rotatable on shaft 113, as an integral unit, are two pulleys 115 and 116. V-belt 107 from drive pulley 106 frictionally engages the pulley 115 to impart rotation to both pulleys 115 and 116. Pulley 116 drives a belt 117 and the belt 117 is reeved around the periphery of the drying drum 70 for imparting rotation to the drum when the motor 90 is energized.

Ann 110 is provided with an ear 120, and the base 35 is provided with a lug 121 substantially vertically aligned with the ear 120. A tension spring 122 is hooked between the ear and lug 121 for biasing the arm 110 downwardly, whereupon a downward pull is at all times applied to the arm 110, and the belt 117 which drives the drying drum 70 is maintained under tension for driving the drum.

Mounted on the end of the motor shaft 103 is a suction fan 124 having a plurality of blades 125. Blades 125 are disposed in the duct 60 closely adjacent and rotatable on an axis concentric with the center of opening 57 and discharge air through the opening 62 which communicates with atmosphere through lint receptacle 23. Operation of the fan causes atmospheric air to enter through louvers 18, pass through inlet opening 66 in the lower portion of pedestal 51 and sweep upwardly over the heating elements 67 interiorly of the pedestal, as shown by the arrows in Figure 6, flow out through openings 65 in the upper end of the pedestal and circulate axially through the revolving drum, and then enter pedestal 50 through the openings 56 and move through opening 57 into the eye of the fan impeller. The air circulation system thus employed draws fresh heated air directly into contact with and through the clothes at relatively high velocity as they are being rotated and tumbled in the drum. A fast drying cycle is thus accomplished to reduce the time that the clothes are subjected to the tumbling action of may occur fromthe drum or drive means therefor is absorbed by the insulation batts "68 mountedbetween the pedestals 'andthe cabinet. There'is'no mechanical connection between the cabinet'lS and the operating structure except at theb'ottom through the relatively rigid base.

Lint receptacle 23,as'previously mentioned, is removable an'd, if desired, an exhaust pipemay be connected 'to communicate with'discharge opening 62 in the event it is desired to pipe the'moisture laden air out of the room. Control system In general, the electrical controlsystem for the motor 90 and heating element 67 comprises a conventional timer mechanism 127 mounted'on thetront Wall of the casing "15, a thermostat 128 located in'stanchion 51 above'the heating element 67, a thermostat 129 in the ductfitl, a door actuated switch 130 and a drum door locatingswitch 'Referringspecifically to Figure 4, three wires 135, 136 and 137 lead from the terminal box '40 and form a230- bolt'circuit 'across'the wires 136 and 137and a l15-volt circuit across the wires 135 and 136. Heating element 67 is connected across the two wires -136 and 137 and connected in series with the heating element circuit is the thermostat 129 located in the outlet duct- 60 and the thermostat 128 locatedabove the heating element 67 in the stanchion 51. Wires 135 and 136 form a motor circuit 7 for the motor 90, the switch 130 being connected in series "with the motor circuit whereby the motor is not energized unless switch 130 is closed and the timer 127 is set.

Switch 131 is also connected in series'with the motor 90 to energize the motor independently of the other control means. Timer'127 has switch ele'ments'138 and 139 connected in series with wires 136 and 137. The timer is of a conventional type which is spring operated and which, upon completion of its time cycle, to which it is set, opens its switches'138,'139 to' open both the heating and motor circuits.

Referring to Figure 3, switches 130 and 131 are mounted on a flange 140 projecting downwardly adjacent the hinge 32 of the housing 15. Switch 130 has a spring pressed button 141 projecting through the flange 140 and the button 141 is adapted to be engaged by a tab 142 secured to the hinge edge of the lid 31 when the lid is closed to close the switch. Switch 130 is thereby open when the lid 31 is open and is closed when the lid is shut. Switch 131, similarly, has a spring pressed button 143 projecting through the flange 140. This button is not engaged by the lid 31 but is manually operable when the lid 31 is open, as will be hereinafter described.

Motor 90 is energized by means of its circuit wires 135 and 136 as long as the timer 127 is set. Heating element 67 is controlled by the timer 127 as well as the two thermostats 128 and 129. Thermostat 129 in the outlet duct 60isadjusted to'open the heating unit circuit when a predetermined temperature has been reached in the outlet duct, such aswhen the clothes reach a dry state, and thermostat 128 adjacent the heating unit 67 is adjusted adjusted'to shutoff the heating 'unit'in such'in'stance.

' described herein.

"motor whenthe 'd'riim door"82 is "open.

'ator opens the cabinet lid '31.

and shields boththes'witch 'a1id'theswitc'h131'so that in no 'possible'way can theop'erator'intentionally or accidentally touch the buttons 141 and 1 1310 energize the When the clothes have been ins'erted'inthedrum; the door 82 and the cabinet lid '3'1'are "closedjthe door 'SZ'b'ein'g securely 'held in closedposition'byits'latch 84. With'the door 82 and'lid 31 shut, swath 1'3'0is heldin'clos'ed'position by tab '142. Timer 127 is'then set to apredetermined drying'ti'me whereby the 'circuits'to'the heating unit and the motor 90 are clos'e'dto 'startthe drying operation.

At the completion or 'a drying operation, when the circuits have beende energiz'ed by timer 127, the 'oper- It the drum has not stopped with its do'dr'atthe'tdp, switch 131 is manually pressed on and olf momentarily to advance the drum to the desired position for removing the clothes therefrom. If the clothes become dry prior to the time limit as set onthe timerfthe temperature in'the outlet duct rises to the point where thermostat 1'29 responds to shut oil? the heating un'it 6 7. Themotor circuit is uninterrupte'dby thermostat 12i9,h( 'wever, and the motor continues to run. When'the outlet duct 6tlhas'cooled to a predetermined temperature, the thermostat 129will re-close the circuit "to cause the heating unit to be 'reenergized. Thermostat 129 thus opens and closes the heating circuit'to maintain a'p'redetermined temperature in the air circuituntil thetirner has reached its time limit to'de-ener'gize the entire sy'stem. Thermostat '129 device. For example, if theo'perator should open'the lid '31 before the'tirn'er opens switch 138, 139, the'heating unit will remain energized but the motor circuitwillbe tie-energized. Without 'force'd movement of the air to carry 'awaythe heat,heating"chamber in stanchio'n51 would become overheated, but the thermostat I28 is The thermostat re-closes the heating'ci'rcuit as soon as 'the temperature in the heating chamber falls to a safe 'value.

'T he present dryer, therefore, affords a fully automatic mechanism which is simple in structure, efficient in operation, and inexpensive to manufacture. The'device'provides top opening m'ea'ns'for convenience in loading and unloading the drum, and provides a novel heated 'air circuit 'for'effectiv'ely during the clothes'in the rotating drum in a minimum of time to conserve electric energy. In addition to' these features and other features described hereinabove, the operating structure, exclusive of the outer cabinet or casing, can be built in a cabinet enclosure comprising a permanentfportion of a dwelling' since the operating mechanism does not require the cabinet 15. Furthermore, the heating unit is not restricted to an electric element, but may comprise, for example, a gas unit having 'a conventional electrical control means therefor'for adaptationto 'the electrical circuit shownand The invention is not restricted toa top opening cabinet but it is understood'that a side 'op''ning cabinet could as well be used in conjunction with the present op'eratingmechanism.

Having now described my invention and in what man- 'ner the same maybe used, what I claim as new and desireto protect by'Letters Patent is:

l. A laundry dryer comprising a laundry drum having to said motor and the other being belted to the periphery of said drum, and a spring connected with said arm to tension the drum belt.

2. A laundry dryer comprising a laundry drum with air inlet and outlet openings in opposite ends of said drum, a base member, a pair of spaced hollow stanchions on said base member arranged on opposite ends of said drum and having openings communicating with said drum inlet and outlet openings, means for supporting said drum on said stanchions rotatably around a horizontal axis, said drum having a peripheral opening therein for loading and unloading laundry, a door on said drum adapted to close the peripheral opening therein, a belt engaging the peripheral surface of said drum between said door and one end of the drum, said stanchion at said one end of said drum having an air opening therein communicating with the atmosphere, a fan operatively associated with said air opening for circulating air through said stanchions and drum, a motor for driving said fan and belt, and air heating means in one ofsaid stanchions.

3. A clothes dryer comprising a clothes receiving drum with air inlet and outlet openings in opposite ends of said drum, a base, a pair of spaced hollow stanchions on said base on opposite ends of said drum and having openings communicating with said drum inlet and outlet openings, seals between said drum ends and said stanchions around said openings, air heating and circulating means operatively associated with said stanchions for producing a current of heated air axially through said drum, means for supporting said drum on said stanchions rotatably around a horizontal axis, said drum having a peripheral opening therein, a door on said drum adapted to close the peripheral opening therein, a cabinet on said base enclosing said drum and stanchions, and said cabinet having an opening adapted to register with said peripheral opening in said drum, and a door for closing said cabinet opening,

4. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, one of said stanchions having an air inlet opening communicating with atmosphere and the other stanchion having an air outlet opening, a cylindrical clothes drum arranged between said stanchions and having openings in the ends thereof communicating with said stanchions, air heating and circulating means in said stanchions, means for mounting said drum on said stanchions rotatably around a horizontal axis, a cabinet hav ing top, side and end walls mounted on said base member and enclosing said drum and stanchions, a door in the peripheral surface of said drum hinged on an axis parallel with the drum axis, a door in said top wall of said cabinet hinged on an axis parallel with said drum axis, and means including a belt drive on the surface of said drum between said drum door and one end of said drum for rotatably driving said drum.

5. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, a horizontal clothes drum between said stanchions, end walls on said drum, central bearing means on said end walls supporting said drum for rotation on said stanchions, said end walls having openings around said bearing means, said stanchions having openings around said bearing means communicating with the openings in said drum end walls, a circular seal between each stanchion and one of said drum end walls surrounding said openings and providing a sealed communication therebetween, and means for heating and circulating air through said stanchions and drum.

6. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, a horizontal clothes drum between said stanchions, flat end walls on said drum, central bearing means on said end walls supporting said drum for rotation on said stanchions, said end walls having openings around said bearing means, fiat walls on said stanchions confronting said drum end walls in parallel relation and having openings therein around said bearing means communicating with the openings in said drum end walls, a circular seal between each stanchion and its respective confronted drum end wall surrounding the openings therein, and means for heating and circulating air through said stanchions and drum.

7. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, a horizontal clothes drum between said stanchions, trunnions supporting the ends of said drum for rotation on said stanchions, said stanchions and drum ends having openings therein around said trunnions, circular sealing rings between said stanchions and drum ends around the openings therein providing a communication therebetween, and air circulating and heating means in said stanchions.

8. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, a horizontal cylindrical clothes drum between said stanchions, trunnions supporting the ends of said drum for rotation on said stanchions, said stanchions and drum ends having axially communicating air circulating openings therein around said trunnions, air heating means in one of said stanchions, said one stanchion having an air inlet opening communicating with atmosphere, the other of said stanchions having an air outlet opening therein, a motor with a belt drive on the peripheral surface of said drum, and means including a suction fan on said motor communicating with the outlet opening in said other stanchion for exhausting air therethrough.

9. A clothes dryer comprising a base member, a pair of spaced hollow stanchions mounted on opposite sides of said base member, one of said stanchions having an air inlet opening communicating with atmosphere and the other stanchion having an air outlet opening, a horizontal cylindrical clothes drum between said stanchions, trunnions supporting the ends of said drum for rotation on said stanchions, said stanchions and drum ends having openings therein around said trunnions, circular sealing rings around said openings between said stanchions and drum ends, air heating means in said one stanchion, a cabinet having top, side and end walls mounted on said base member and enclosing said drum and stanchions, a door in the peripheral surface of said drum hinged on an axis parallel with the drum axis, a door in said top wall of said cabinet hinged on an axis parallel with said drum axis, a motor with a belt drive on the peripheral surface of said drum between the drum door and one end or" the drum, and a suction fan on said motor at said outlet opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,060,801 Watkins May 6, 1913 1,575,965 Braley Mar. 9, 1926 2,393,380 Jorgenson et al Jan. 22, 1946 2,570,437 Ellis Oct. 9, 1951 2,679,112 Thompson May 25, 1954 FOREIGN PATENTS 44,855 Germany Oct. 22, 1888 

